Microtome bypass slide



Aug. 9, 1960 Filed Jan. 9, 1958 J. BLUM 2,948,190

MICROTOMEBYPASS sums:

2 Shets-Sheet 1 BY 7 ATTORNEY 2,2 I I 45 4/ 7 V A k Aug. 9, 1960 J. BLUM} MICROTOME BYPASS SLIDE Filed Jan. 9.---195a TiE'A- INVENTOR JZJEF 54 UM ATTOZNEY United States Patent MICROTOME BYPASS SLIDE Josef Blum, Norwalk, Conn., assignor to Ivan' Sorvall, 1 'Inc., Norwalk, Conn., a corporation of New York Filed Jan. 9, 1958, Ser. No. 707,965

8 Claims. or. 88-40) This invention relates to laboratory instruments and the like, and particularly to a bypass mechanism for the speci- Q and now Patent No. 2,822,726, issued February 11, 1958.

In that patent there is described a microtome which is adapted to produce ultra thin tissue sections of equal thickness for both optical and electron microscopy. For many requirements it is desirable to provide a plurality of successive specimen sections of equal thickness; accordingly, the apparatus is adjusted to advance the specimen toward the cut-ting knife in precisely controlled equal increments. In some instances, however, the characteristics of the specimen or the manner in which it is to be processed and examined may require a section thickness that is dilferent from that for which the apparatus has been-adjusted, and ordinarily, a readajustment of the specimen advancing mechanism must be arranged, with consequent further readjustments for subsequent specimen sections of still different thicknesses.

The necessity for making such repeated readjustments in the specimen advancing mechanism of the microtome apparatus is obviated by the present invention which permits the production of successive specimen sections of varying thicknesses with a minimum of effort on the part of the operator.

The specimen advancing means in the above mentioned patent causes the specimen todescribe an orbit Whose plane isdisposed at an angle relative to the edge of the cutting knife. In'this mannerthe specimen bypasses the knife during a portion of each cycle, during which bypass time the specimen is advanced toward the knife, by a precisely. predetermined increment. The orbital path of the specimen holder is defined by a suitably contoured aperture in the guide plate through which it extends. Normally the successive traverses of the specimen across the cutting knife produce successive slices of specimen sections of equal thickness.

When it is desired to produce a specimen section of a difierent thickness, I now provide a simple bypass mechanism which changes the contour of the guide plate aperture and prevents the specimen holder from carrying the specimen across the cutting edge of the knife, while at the same time repeated cycling of the holder takes place with the advancing mechanism operating to advance the specimenat repeated equal increments. Knowing the exact specimen advance increment for each cycle of the holder, .the operator divides the desired thickness of the specimen section by said increment dimension and arrives at the number of bypass cycles that are necessary'. 'Then the operator adjusts the bypass mechanism, to be' described herein, whereby the holder automatically causes the specimen to bypass the knife the determined number of cycles, after which the bypass mechanism is released to permit the specimen, in its next cycle, to traverse the knife whereupon a section of the desired thickness is cut.

In producing subsequent tissue sections of varying thicknesses, the foregoing procedure is followed by causing the bypass mechanism to be operative only for a number of cycles that is the requisite multiple of the basic specimen advancing increment to which the apparatus is adjusted. I

Still other objects and advantages of my invention will be apparent from the specification.

The features of novelty which I believe to be characteristic of my invention are set forth herein and will :best be understood, both as to their fundamental principles and as to their particular embodiments, by reference to the specification and accompanying drawings, in which:

Figure 1 is a side perspective view of the microtome embodying the present bypass invention;

Fig. 2 is an enlarged face view, taken on line 2-2 of Fig. 1;

Fig. 3 is a further enlarged section view taken on line 3-3 of Fig. 2;

Fig. 4 is an elevation of the guide plate showing a porvtion of the'b-ypass slide in its operative position;

Fig. 5 is a greatly enlarged top section view of a fragment of the bypass slide together with its control spring and stud when said slide is in the position shown in Fig. 4;

Fig. 6 is an elevation view, similar to Fig. 4, showing the bypass slide retracted;

Fig. 7 is a greatly enlarged top section view, similar to Fig. 5, showing the bypass slide in the retracted position', as indicated in Fig. 6; and

Fig. 8 is an enlarged perspective view of the bypass slide.

Referring now to the drawings in detail, there is shown in Fig. 1 a perspective side view of a microtome whose parts and functions are described in great detail in said Patent No. 2,822,726. A salient feature of that apparatus is the provision of a specimen advancing bar 11 Whose rear end is pivotally mounted on block 12 which in turn is pivotally mounted within yoke 13. This compound pivot mounting, which is more fully described in said patent, provides for the orbital movement of the forward end of the specimen advancing bar in all lateral directions relative to the cutting edge 14 of cutting knife 15 which is suitably supported on a stage 16. Adjustably mounted on base 17, on the forward end of specimen advancing bar 11 is a biological tissue specimen 18, which is caused to pass across the edge 14 of knife 15, whereby a section of tissue is cut from said specimen.

Mounted securely on base 17 is a vertical frame 21,

; near the upper end of which is an aperture 22. Connected to frame 21 is a guide plate 23 whose peripheral areas extend past the edges of aperture 22 and whose central portion is cut out in the form of guide aperture 24. Specimen advancing bar 11 extends through both apertures 22*and 24. Since the area of guide aperture 24 is somewhat smaller than that of aperture 22, it is evident that the orbital motion of bar 11 is defined by the contours of the aperture 24.

As shown in Fig. 6, aperture 24 is provided with a contour comprising a starting recess A at the top of said aperture which is offset slightly to the right from vertical edge B of said aperture. The lower portion of aperture 24 is defined by a downwardly obliquely descending edge C which terminates in a return recess D which is slightly offset from the vertical edge E. The upper portion of as indicated by the arrows in Fig. 6. As bar 11 deaperture &2 in frame 21.

scends along edge B, the specimen i8 is caused to pass across the edge 14 of knife 15 whereby a thin section of tissue is removed therefrom. Upon continued movement, bar 11 moves along edge C and then returns along edge D and then along edges E and G to starting recess A. The return path of bar 11 along edges E and G causes specimen 18 to bypass knife 15.

As described in the above mentioned patent, the microtome is arranged to produce repeated slices of the specimen in accordance with a predetermined thickness as desired by the operator of the machine by adjusting the various controls as described therein. It is often desirable, however, to provide specimen tissue sections of varying thicknesses depending upon the different requirements of examining procedures, staim'ng conditions and of either electron or optical microscopes. Consequently, in order to permit the cutting of sections of different thicknesses, as desired, I provide a flat bypass slide plate 31 which is movable laterally within a slotted recess in one face of frame 21. The upper edge 32 and lower edge 33 of slide plate 31 are rearwardly bevelled and they mate with correspondingly bevelled upper and lower edges of said slot which serves as a sliding guide for said slide plate. The outer end of slide plate 31 terminates in an angled extension 34, the inner surface of which is provided with a pair of spaced apart recesses 35 (Fig. 8), which accommodate the respective ends of a pair of captive springs 36. The greater portions of springs 36 are captive within respective recess 37 in frame 21. The action of springs 36 normally urges slide plate 31 laterally outwardly from frame 21, as indicated in its position shown in Figs. 6 and 7.

Slide plate 31 has a longitudinal slot 38 which terminates at one end in a circular aperture 39. A knurled headed stud 41 is movable longitudinally within an Near the rear end of stud 41 is a first annular recess 43 which accommodates the legs 44 of one end of spring 4-5, whose other end is secured to the back wall of frame 21 by means of screw 46. Near the knurled head of stud 41 is a second annular recess 47 which cooperates with slot 38 in slide plate 31 to prevent longitudinal motion of stud 41 when said bar is in its disengaged position as indicated in Figs. 6 and 7.

Normally stud 41 is depressed as in Fig. 7, whereby springs 37 urging against extension 34 cause slide plate 31 to move laterally from frame 21 to the extent limited by the end of slot 38 impinging against recess 47 of stud 41. In this position of slide plate 31, Figs. 6 and 7, aperture 24 is unobstructed and bar 11 freely performs its successive cycles to cause repeated sections of equal thickness to be cut from the specimen.

When, however, it is desired to cause the specimen to bypass the knife for several cycles in order to produce a thicker section than would otherwise result, slide plate 31 is pressed manually inwardly by pushing against extension 34 whereby slot 33 moves along recess 47 of stud .41 until aperture 39 in plate 31 is coaxially opposite said stud whereupon spring 45 causes the main body portion thereof to move into aperture 39 thereby locking slide plate in position, as shown in Fig. 5.

The inner end of slide plate 31 is contoured in such a manner that when it is in position as shown in Figs. 3 and 4, it protrudes across a portion of guide aperture 24 and causes the specimen advancing bar 11 to oscillate only in a path along edges E and G, as shown by the arrows in Fig. 4-. The inner end of slide bar plate 31 is provided with an oblique upper edge 51 which descends to join a vertical edge 52 to form with edges E and G of aperture 24- a confined pathway, as shown in Fig. 4, wherein specimen advancing bar 11 moves reciprocally in its cyclic motion thereby causing the specimen on the end of said bar to bypass the cutting edge of the knife during each cycle of advancing motion. A laterally extending beveled spur 53 at the lower end of edge 52 has an upper oblique edge 54 which coincides with edge C of aperture 24 to assist in urging bar 11 toward return recess D in said aperture.

Since the microtome is arranged to produce equal increments of advancing motion for each cycle of rotation of the specimen advancing bar Within aperture 24 of guide plate 23, it is evident that by counting the number of cycles by which the specimen is bypassed from the knife and multiplying said number by the predetermined incremental advance, it is possible to determine the thickness of the specimen desired, at which time the bypass slide piate 31 is removed from aperture 24 by pressing upon the knurled head of stud 41 whereupon annular recess 47 is brought into the path of slot 38 thereby permitting springs 37 to urge plate 31 automatically into its operative position, as shown in Figs. 6 and 7. Thereupon the next cycle of motion of specimen advancing bar 11 causes the specimen on the end thereof to cross the cutting edge 14 of knife 15 to produce a tissue section of the desired thickness.

in the specification, I have explained the principles of invention, and the best mode in which I have contemplated applying those principles, so as to distinguish my invention from other inventions; and I have particularly pointed out and distinctly claimed the part, mode or combination which I claim as my invention or discovery.

While I have shown and described certain preferred embodiments of my invention, it Will be understood that modifications and changes may be made without departing from the function and scope thereof, as will be clear to those skilled in the art.

I claim:

1. A microtome having a cutting knife and a specimen advancing bar which is caused cyclically to advance a specimen toward said knife in predetermined equal increments, comprising a support, a guide plate on said support, an aperture in said guide plate through which said bar extends, said bar slidably engaging the edges of said aperture for producing an orbital motion of said bar for each specimen advancing cycle of movement thereof, the contour of said aperture being arranged to cause the specimen on said bar to be cut by said knife during one portion of each cycle and to bypass said. knife during another portion of each cycle, a slide plate movably supported on said support and adapted to be removably positioned at will across a portion of said aperture, the edge portion of said slide plate that is superimposed across said aperture being contoured in a manner to cooperate with the edge of the remainder of said aperture to cause said bar to move in a restricted path excluding that portion of movement through which said bar carries the specimen across the cutting edge of said knife.

2. A microtome according to claim 1 wherein said slide plate is movable at will into and out of a position across a portion of said aperture during any of the cycles of operation of said specimen advancing bar.

3. A microtome according to claim 1, and further comprising means on said support and bearing against said slide plate normally urging the latter into a retracted position from said aperture and means on said support and cooperating with said slide plate to retain said plate in position against the action of said first means whereby said plate is superimposed across a portion of said aperture.

4. A microtome according to claim 1, and further comprising a spring connected between said support and said slide plate normally causing said plate to be retracted from said aperture, a second aperture in said support, a slot in said plate, a stud extending through and movable within said'second aperture and said slot, said stud in one position acting against the action of said spring to retain said slide plate in a position where the latter is superimposed across a portion of the first mentioned aperture, and said stud in another position releasing said slide plate whereby the latter is caused by the action of said spring to be retracted from said first mentioned aperture.

5. A rnicrotome according to claim 4, and further comprising a second spring normally urging said stud into a position to cause the latter to retain said plate in a location to cover a portion of said first mentioned aperture.

6. A microtome system comprising a knife, means for cyclically advancing a specimen toward the knife in equal increments to be sliced by the latter, said means passing said specimen in an orbital path relative to said knife whereby during one part of each advancing cycle said specimen is passed across the cutting edge of said knife and during another part of said cycle said specimen bypasses said cutting edge, and means operable at will for restricting the movement of said first means to a path only where said specimen bypasses the cutting edge of said knife during each cycle of its incremental advance.

7. A microtome system wherein a specimen is cyclically advanced in equal increments toward a cutting knife, comprising a cutting edge on said knife, means for causing said specimen to move in an orbital path relative to said knife whereby during one part of each advancing cycle said specimen is passed across the cutting edge of said knife and during another part of said cycle said specimen bypasses said cutting edge, and means operable at will for restricting the movement of said first mentioned means to a path only where said specimen bypasses the cutting edge of said knife during each cycle of its incremental advance.

8. A microtome system comprising first means for repeatedly moving a specimen in equal cyclical increments relative to a cutting knife for producing tissues of substantially equal basic thickness from said specimen, second means in said system positionable at will in two different locations relative to said first means, said second means in the first location being operable to prevent said specimen from crossing the cutting edge of said knife while said first means are in operation during any selected successive number of cycles whereby a section of tissue of a desired multiple of the basic thickness is produced, and in the second location permitting said first means to resume the repeating cutting action of said knife upon said specimen, third means normally urging said second means into said second location, and fourth means for releasably securing said second means in said first location against the action of said third means.

References Cited in the file of this patent UNITED STATES PATENTS 403,169 Woodmansee May 14, 1889 1,350,094 Davis Aug. 17, 1920 2,155,523 Bausch et al. Apr. 25, 1939 2,811,871 Gauba-tz Nov. 5, 1957 

